In general, an image processing apparatus, such as a multifunctional peripheral (MFP) including a printer, scanner, facsimile machine, and copier or functions thereof, includes a communicating unit (such as a NIC (Network Interface Card) or modem (Modulator-Demodulator)) that communicates with an external apparatus (such as a computer or other image processing apparatuses) through a communication medium such as a network or telephone lines. Some of such image processing apparatuses include a function (hereinafter, a sleep function) for shifting to a power saving state (generally, referred to as a sleep mode) with lower power consumption than a normal operation state (hereinafter, an operating state) if no operation is performed for an operation input unit included in the image processing apparatus and no data are received from the external apparatus through the communicating unit for a certain time period or more. In the power saving state, for example, energization (power supply) is discontinued for a fixing device including a heater and devices such as a control circuit, while the communicating unit is often maintained in an energized state. This is because in the power saving state, energization of devices in a non-energized state is resumed automatically in response to a request from the external apparatus to allow the devices to automatically return to the operating state. For example, in an image forming apparatus shown in Japanese Laid-Open Patent Publication No. H8(1996)-101606, when an energized communicating unit receives a print request in a power saving state, the entire apparatus is applied with current to form an image in accordance with the received print request.
The requests from the external apparatuses include various requests such as a print request that requests to form an image on a recording paper sheet, an image scan request that requests to read an image formed on a document, and a request for performing processing of accessing a storage unit such as a hard disk included in the image processing apparatus to manipulate a data file (hereinafter, a data filing processing). The data filing processing may be processing of writing or updating data, reading data, erasing data, and changing data file names, for example.
On the other hand, in an image forming apparatus shown in Japanese Laid-Open Patent Publication No. 2005-186425, when an energized controller receives an access request for a hard disk from an external apparatus through a network in a power saving state, energization of the hard disk is started to perform the requested processing.
In an MFP shown in Japanese Laid-Open Patent Publication No. 2003-63101, when a print request is received through an external interface in a power saving state where a sub-CPU and the external interface are supplied with electric power from a subsidiary power supply, the sub-CPU supplies electric power to a main CPU controlling the entire apparatus to perform printing.
However, when a number of image processing apparatuses held by corporations, etc., individually have a function of setting a condition of shifting to a power saving state and a condition of returning from the power saving state, there has been a problem that a work of setting these conditions individually at these apparatuses is burdensome and at the same time, overall power saving control is hard to achieve.
There has also been a problem that when an apparatus, while in the power saving state, is requested to perform some processing by an external apparatus through a communicating unit or by an operation to a predetermined operation unit, constantly responding to such request by starting application of current to many devices not current-applied and executing the requested processing do not sufficiently achieve sufficient electric power saving.
Furthermore, there has been a problem that when, in a situation where each of many image processing apparatuses is in a power saving state, judgment is made of whether to return to an operating state depending on the situation such as contents of the incoming request for processing, each of many image processing apparatuses, even in the power saving state, must keep a calculating device of making various kinds of judgment in a current-applied state, and sufficient power saving can not be achieved.